Throughout the decade of the 1980's, despite the elimination of lead from gasoline and reductions of lead emissions from regional industry, concentrations of lead and other metals remained high in harbor sediments in New York and New Jersey. There appears therefore to be a "missing" or unidentified source of lead in the New York-New Jersey environment that is compensating for declines in traditional sources. Potential candidates include industrial and incinerator emissions to air, drinking water delivery systems and interior and exterior paints. Heavy metal fluxes have not been monitored directly and must therefore be estimated by indirect means. The goal of this project is to identify previously unrecognized urban sources of environmental lead using dated environmental samples. This strategy will enable us to deconvolve the major sources and pathways of lead to the urban environment over the past few decades, and will be guided by the following hypotheses: 1. Exterior lead paints in the New York City area contribute a significant portion of the "missing" lead source that has kept lead levels high in New York-New Jersey harbor sediments. 2. The transfer of gasoline lead from land to New York-New Jersey harbor sediments is slow (at least 10-15 years) process that has helped to maintain high lead concentrations in harbor sediments. 3. Most of the lead that is deposited in New York-New Jersey harbor sediments has passed through Water Pollution Control Plants. The samples to be utilized are: 1) airborne particulates from weekly air filters which have been collected and archived since 1966, 2) dated sediment cores from New York Harbor, bays and tributaries, 3) dated sediment cores for the New York city reservoir system, 4) soil cores from parks and areas near bridges, 5) water samples taken from throughout the water delivery system (reservoir to tap, and especially tap water in areas of the city where the New York city Department of Environmental Protection has identified problems for lead) and 6) sewage sludge from New York City Water Pollution Control Plants (WPCP). We will measure Pb and other metal concentrations (Cr, Cd, V, Cu, Zn, As, Ni, Mn, Sn, Hg, Sr, Ag, Fe, Al, Ti, Ba) as well as lead-isotopic fingerprints for the various sources of Pb to the NYC environment (pipes, solder, sewage outfall, combined sewer overflow, paints (including paints from bridges), vehicle exhausts, oil combustion, incinerators, and battery industries. Data obtained from this study will provide information on major current sources of lead exposure for urban populations. These data will be essential for development of rational strategies of exposure prevention.